Merge pull request #267074 from linglingye001/linglingye/FeatureManagementInAks

K8s provider: quickstart for using feature management in AKS

Author: v-ccolin

articles/azure-app-configuration/TOC.yml

@@ -41,6 +41,8 @@
           href: quickstart-feature-flag-spring-boot.md
         - name: Azure Functions
           href: quickstart-feature-flag-azure-functions-csharp.md
+        - name: Azure Kubernetes Service
+          href: quickstart-feature-flag-azure-kubernetes-service.md
     - name: Service integration
       items:
         - name: Azure Kubernetes Service

articles/azure-app-configuration/media/quickstarts/kubernetes-provider-feature-flag-beta-page.png

@@ -0,0 +1,187 @@
+---
+title: Quickstart for using Azure App Configuration Feature Management in Azure Kubernetes Service
+description: In this quickstart, create an ASP.NET core web app and use feature flag in it running in AKS and use the Azure App Configuration Kubernetes Provider to load key-values and feature flags from App Configuration store.
+services: azure-app-configuration
+author: linglingye
+ms.service: azure-app-configuration
+ms.devlang: csharp
+ms.custom: devx-track-csharp
+ms.topic: quickstart
+ms.date: 02/23/2024
+ms.author: linglingye
+#Customer intent: As an Azure Kubernetes Service user, I want to manage all my app settings in one place using Azure App Configuration.
+---
+
+# Quickstart: Add feature flags to workloads in Azure Kubernetes Service
+
+In this quickstart, you'll create a feature flag in Azure App Configuration and use it to dynamically control the visibility of a new web page in an ASP.NET Core app running in AKS without restarting or redeploying it.
+
+## Prerequisites
+
+Follow the documents to use dynamic configuration in Azure Kubernetes Service.
+
+* [Quickstart: Use Azure App Configuration in Azure Kubernetes Service](./quickstart-azure-kubernetes-service.md)
+* [Tutorial: Use dynamic configuration in Azure Kubernetes Service](./enable-dynamic-configuration-azure-kubernetes-service.md)
+
+## Create a feature flag
+
+Add a feature flag called *Beta* to the App Configuration store and leave **Label** and **Description** with their default values. For more information about how to add feature flags to a store using the Azure portal or the CLI, go to [Create a feature flag](./quickstart-azure-app-configuration-create.md#create-a-feature-flag).
+
+> [!div class="mx-imgBorder"]
+> ![Screenshot showing creating feature flag named Beta.](./media/add-beta-feature-flag.png)
+
+## Use a feature flag
+
+In this section, you will use feature flags in a simple ASP.NET web application and run it in Azure Kubernetes Service (AKS). 
+
+1. Navigate into the project's directory you created in the [Quickstart](./quickstart-azure-kubernetes-service.md), and run the following command to add a reference to the [Microsoft.FeatureManagement.AspNetCore](https://www.nuget.org/packages/Microsoft.FeatureManagement.AspNetCore) NuGet package version 3.2.0 or later.
+
+    ```dotnetcli
+    dotnet add package Microsoft.FeatureManagement.AspNetCore
+    ```
+
+1. Open *program.cs*, and add feature management to the service collection of your app by calling `AddFeatureManagement`.
+
+    ```csharp   
+    // Existing code in Program.cs
+    // ... ...
+
+    // Add a JSON configuration source 
+    builder.Configuration.AddJsonFile("config/mysettings.json", reloadOnChange: true, optional: false); 
+
+    // Add feature management to the container of services.
+    builder.Services.AddFeatureManagement();
+
+    var app = builder.Build();
+
+    // The rest of existing code in program.cs
+    // ... ...
+    ```
+    
+    Add `using Microsoft.FeatureManagement;` at the top of the file if it's not present.
+
+1. Add a new empty Razor page named **Beta** under the *Pages* directory. It includes two files *Beta.cshtml* and *Beta.cshtml.cs*.
+
+    Open *Beta.cshtml*, and update it with the following markup:
+
+    ```cshtml
+    @page
+    @model MyWebApp.Pages.BetaModel
+    @{
+        ViewData["Title"] = "Beta Page";
+    }
+
+    <h1>This is the beta website.</h1>
+    ```
+
+    Open *Beta.cshtml.cs*, and add `FeatureGate` attribute to the `BetaModel` class. The `FeatureGate` attribute ensures the *Beta* page is accessible only when the *Beta* feature flag is enabled. If the *Beta* feature flag isn't enabled, the page will return 404 Not Found.
+
+    ```csharp
+    using Microsoft.AspNetCore.Mvc.RazorPages;
+    using Microsoft.FeatureManagement.Mvc;
+
+    namespace MyWebApp.Pages
+    {
+        [FeatureGate("Beta")]
+        public class BetaModel : PageModel
+        {
+            public void OnGet()
+            {
+            }
+        }
+    }   
+    ```
+
+1. Open *Pages/_ViewImports.cshtml*, and register the feature manager Tag Helper using an `@addTagHelper` directive:
+
+    ```cshtml
+    @addTagHelper *, Microsoft.FeatureManagement.AspNetCore
+    ```
+
+    The preceding code allows the `<feature>` Tag Helper to be used in the project's *.cshtml* files.
+
+1. Open *_Layout.cshtml* in the *Pages*\\*Shared* directory. Insert a new `<feature>` tag in between the *Home* and *Privacy* navbar items, as shown in the highlighted lines below.
+
+    :::code language="html" source="../../includes/azure-app-configuration-navbar.md" range="22-36" highlight="6-10":::
+
+    The `<feature>` tag ensures the *Beta* menu item is shown only when the *Beta* feature flag is enabled.
+
+1. [Containerize the application](./quickstart-azure-kubernetes-service.md#containerize-the-application) and [Push the image to Azure Container Registry](./quickstart-azure-kubernetes-service.md#push-the-image-to-azure-container-registry). 
+
+1. [Deploy the application](./quickstart-azure-kubernetes-service.md#deploy-the-application). Refresh the browser and the web page will look like this:
+
+    ![Screenshot showing Kubernetes Provider after using configMap without feature flag.](./media/quickstarts/kubernetes-provider-feature-flag-no-beta-home.png)
+
+## Use Kubernetes Provider to load feature flags
+
+1. Update the *appConfigurationProvider.yaml* file located in the *Deployment* directory with the following content.
+   
+    ```yaml
+    apiVersion: azconfig.io/v1
+    kind: AzureAppConfigurationProvider
+    metadata:
+      name: appconfigurationprovider-sample
+    spec:
+      endpoint: <your-app-configuration-store-endpoint>
+      target:
+        configMapName: configmap-created-by-appconfig-provider
+        configMapData: 
+          type: json
+          key: mysettings.json
+      auth:
+        workloadIdentity:
+          managedIdentityClientId: <your-managed-identity-client-id>
+      featureFlag:
+        selectors:
+          - keyFilter: 'Beta'
+        refresh:
+          enabled: true
+    ```
+
+    > [!TIP]
+    > When no `selectors` are specified in `featureFlag` section, the Kubernetes Provider will not load feature flags from your App Configuration store. The default refresh interval of feature flags is 30 seconds when `featureFlag.refresh` enabled. You can customize this behavior via the `featureFlag.refresh.interval` parameter.
+
+1. Run the following command to apply the changes.
+
+    ```console
+    kubectl apply -f ./Deployment -n appconfig-demo
+    ```
+
+1. Update the **Beta** feature flag in your App Configuration store. Enable the flag by selecting the checkbox under **Enabled**.
+
+1. After refreshing the browser multiple times, the updated content will become visible once the ConfigMap has been updated within 30 seconds.
+
+    ![Screenshot showing Kubernetes Provider after using configMap with feature flag enabled.](./media/quickstarts/kubernetes-provider-feature-flag-home.png)
+
+1. Select the **Beta** menu. It will bring you to the beta website that you enabled dynamically.
+
+    ![Screenshot showing beta page Kubernetes Provider after using configMap.](./media/quickstarts/kubernetes-provider-feature-flag-beta-page.png)
+
+## Clean up resources
+
+Uninstall the App Configuration Kubernetes Provider from your AKS cluster if you want to keep the AKS cluster.
+
+```console
+helm uninstall azureappconfiguration.kubernetesprovider --namespace azappconfig-system
+```
+
+[!INCLUDE[Azure App Configuration cleanup](../../includes/azure-app-configuration-cleanup.md)]
+
+## Next steps
+
+In this quickstart, you:
+
+* Added feature management capability to an ASP.NET Core app running in Azure Kubernetes Service (AKS).
+* Connected your AKS cluster to your App Configuration store using the App Configuration Kubernetes Provider.
+* Created a ConfigMap with key-values and feature flags from your App Configuration store.
+* Ran the application with dynamic configuration from your App Configuration store without changing your application code.
+
+To learn more about the Azure App Configuration Kubernetes Provider, see [Azure App Configuration Kubernetes Provider reference](./reference-kubernetes-provider.md).
+
+To learn more about feature management capability, continue to the following tutorial.
+
+> [!div class="nextstepaction"]
+> [Enable features for targeted audiences](./howto-targetingfilter-aspnet-core.md)
+
+> [!div class="nextstepaction"]
+> [Use feature filters for conditional feature flags](./howto-feature-filters-aspnet-core.md)